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Basic Concepts of Complex Assemblies | 479
Basic Concepts of Complex Assemblies
Assemblies can consist of any number of externally referenced and local parts.
You can also have any number of subassemblies, both local and externally
referenced. The advantage to having externally referenced parts and subas-
semblies is that you can use the files in any number of assembly files.
In complex assemblies, the same part is often used in multiple locations. Each
part definition defines a unique part. By instancing a part definition, you can
create multiple copies of a part while maintaining only one definition in your
drawing. Any change to the part definition affects all instances of the part.
After building the assembly, you check for interference between the parts, and
perform mass properties calculations to ensure that the parts are designed cor-
rectly. If a design change affects a part used in more than one assembly, make
the change in the external file.
In a previous tutorial, you made changes to an external part from within an
assembly file by editing in place. In this tutorial, you open an external file and
modify it directly. Then you update the assembly file to reflect the changes,
set up scenes to illustrate the assembly, in both exploded and non-exploded
views, create a parts list, and finalize the drawing for plotting.
Starting the Assembly Process
There are two ways to approach the design process; start by thinking about
how the assembly is organized and decide the order in which to instance the
local and external parts into the assembly, or start designing immediately
and then reorganize the hierarchy of the assembly as needed, using assembly
restructure. Constraints are maintained with parts and subassemblies that are
moved in the restructure process.
The assembly restructure feature provides more flexibility in the design pro-
cess. You can place or create an assembly of components at a single level and
subsequently adjust the assembly structure, grouping components into sub-
assemblies for manufacturing, inventory, and other uses.
For more information about using assembly restructure, see Restructuring
Assemblies on page 504.